Hypoglycemia

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Hypoglycemia

Anas saad alsaab

:Objectives

• Define hypolgycemia (Whipple’s triad).

• State the reference range for plasma glucose and describe the endocrine control of plasma glucose concentration.

Define hypolgycemia (Whipple’s triad).

is a condition characterized by abnormally low blood glucose levels, usually less than 70 mg/dl that may

induce symptoms or signs such as altered mental status and/or sympathetic nervous system stimulation. (ADA )

is a clinical situation characterized by a reduction in plasma glucose concentration to a level that may induce symptoms or signs such as

altered mental status and/or sympathetic nervous system stimulation

Whipple's triad  A combination of three clinical features that indicate the presence of an insulinoma:

• presence of symptoms of hypoglycemia

• A low plasma glucose measured at the time of the symptoms

• Relief of symptoms when the glucose is raised to normal.

•

SYMPTOMS

State the reference range for plasma glucose

• Reference ranges are as follows:

• Fasting plasma glucose: 70-99 mg/dL

• Postprandial plasma glucose at 2 hours: Less than 140 mg/dL

• Random plasma glucose: Less than 140 mg/dL

• Values for diabetes mellitus are as follows:

• Fasting plasma glucose: Greater than 126 mg/dL

• Random plasma glucose: Greater than 200 mg/dL

• Postprandial glucose at 2 hours: Greater than 200 mg/dL

• The value for hypoglycemia is as follows:

• Value less than 60 mg/dL

describe the endocrine control of plasma glucose concentration.

• There are two categories of endocrine influences.

a)Hormone which will decrease the blood glucose levels : Insulin

b)Hormones which will increase the blood glucose levels: Glucagon, Epinephrine, Cortisol, Growth

Hormone (GH).

•

Insulin:

Insulin Release from the Beta Cells.

Factors increasing the secretion of insulin:

1. Glucose – Most potent stimulator of insulin secretion.

2. Gastrointestinal hormones:

Gastrin, Secretin, Pancreozymin.

3. Protein and aminoacids: Leucine and Arginine

4. Beta adrenergic and parasympathetic stimulation.

5. Glucagon and Growth hormone

6. Drugs: Tolbutamide

7. Incretin hormones: These hormones work to increase insulin secretion.

Examples (GLP) (GIP)

Factors decreaingthe secretion of insulin:

1. Epinephrine –

During stressful and during exercise, adrenal medulla releases adrenaline.

This suppresses insulin release and mobilizes glucose from liver for energy purpose.

2. Alpha adrenergic stimulation.

• Fat metabolism – Lipogenesis (+)

Lipolysis (-)

• Protein metabolism - Amino acid uptake by cells(+)

Protein synthesis (+)

Protein catabolism (-)

• Carbohydrate metabolism – Glycolysis (+)

Gluconeogenesis (-)

Glycogenesis (+)

Glycogenolysis (-)

GlucagonGlucagon Release from the alpha Cells.

:Increases blood glucose concentration, i.e. Hyperglycemic Effects

Breakdown of liver glycogen (glycogenolysis)Can cause blood glucose to double within a few minutes

Increase gluconeogenesis in the liverIncreased uptake of amino acids which are then used to make glucose

:Regulation of Glucagon Secretion

• Blood glucose – most potent regulator

• Increased amino acids in the circulation

• Especially arginine and alanine

• Catecholamines

• Gastrointestinal hormones (cholecystokinin, gastrin, GIP)

• Glucocorticoids

• Sympathetic and parasympathetic stimulation

• Exercise

Epinephrine

epinephrine keeps certain body tissues, such as muscle, from using as much glucose from the

bloodstream, and it acts to reduce insulin secretion.

Epinephrine is the same “fight or flight” hormone that revs the body up in response to danger, and it produces the symptoms that normally

In some cases, especially when glucagon and epinephrine fail to adequately raise blood glucose levels, the body releases cortisol and growth hormone, which can also increase blood glucose levels.

– The second early response hyperglycemic hormone.– Epinephrine causes glycogenlsis , gluconeogenesis , Lipolysis

– It also stimulates glycolysis in muscle

•

increases gluconeogenesis,

decresases peripheral utilization of glucose,

inhibits glycolysis

Growth Hormone (GH)

• Increased liver glucose 6 phosphatase activity• Prevents peripheral utilization of glucose by inhibiting

phosphorylation.• Antiinsulinic effect on peripheral tissues- adrenal diabetes• Thus leads to hyperglycemia

facilitate glucose production and limit glucose utilization, but neither of them plays a critical role. Their effects are not immediate (delayed for about 6 hours); thus,

they are mostly involved in defense against prolonged hypoglycemia

cortisol

Summary

•

Resources•

• 

http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hypoglycemia-low-blood.html

http://www.oxfordreference.com/view/10.1093/oi/authority.20110803122042314

http://emedicine.medscape.com/article/122122-overview

http://emedicine.medscape.com/article/2087913-overview#aw2aab6b3

Questions

Done by: Anas saad alsaab.